Photograph by: Arlen Redekop
, Vancouver Sun

Climate change is pushing British Columbia’s ecosystems – and its productive forests – farther and farther out of sync with the weather conditions they need in order to thrive, new research suggests.

B.C.’s 16 major ecosystems — everything from coastal rainforest to alpine peaks — are getting left behind as precipitation and temperature patterns shift around in response to global warming.

The trend is expected to create challenges for commercial species such as lodgepole pine which will have less moisture to sustain them through hotter, drier summers, and opportunities for frost-averse species such as Douglas fir to extend their range.

The ‘climate envelopes’ that sustain those ecosystems have migrated — often to the north, sometimes to the east, and even up barren mountainsides — by 23 per cent from their boundaries in 1970, according to projections.

The researchers, who are from the University of B.C. and the B.C. and Canadian forest services, said that they did not expect a 23 per cent average shift to emerge until the 2020s.

“The magnitude of this change was surprising,” they wrote in recent paper titled Projecting Future distributions of ecosystem climate niches. The study focused on vegetation, not fauna.

The 23 per cent shift is an average across all 16 ecosystems. In some cases, the climate shift has already stranded as much as 77 per cent of ecosystems, and “impacts on B.C. ecosystems will intensify as climate change accelerates in future periods.”

UBC forest sciences associate professor Tongli Wang, who did the number-crunching for the paper, said a small decline in average precipitation over the past 40 years “has caused a surprising amount of mismatch between the ecosystem and climate zones.”

“People think about future [climate] change, but actually the change that has happened already is so big,” Wang said.

The challenge for B.C., he said, is to ensure that forest management practices — such as replanting areas after logging — take into account the ability of seedlings to adapt to climate shifts.

“For B.C., climate change is a definite challenge but it also provides opportunities if we match the species with the right climate.”

Catherine Cobden, interim president and CEO of the Forest Products Association of Canada, said the climate shift “absolutely is a business issue.”

“This is a critical area for monitoring,” Cobden said, noting the devastation caused to B.C.’s Interior forests by the mountain pine beetle infestation.

“From our perspective, mitigating climate change risk and figuring out how to adapt — which species may be more disease resistant, that kind of thing — is a business imperative issue now, not just an environmental issue.”

Climate is the “single largest determinant of where you find a particular ecosystem and where you will find a particular plant species,” Sally Aitken, director of UBC’s centre for forest conservation genetics, said.

The centre, which receives funding from both Genome Canada and Genome BC, is working to identify which individual trees within a particular species possess the traits that give them the best chance to survive climate transitions over a multi-decade growing cycle — such as drought resistance, for example.

“What’s hard to predict is what will happen to these forests that are no longer within their climatic niche, their climatic habitat. That, we really don’t know,” Aitken said. “Will insects and diseases come in and kill them or will old trees – which are pretty resilient in a lot of cases – just continue to persist for a long time in those places? Or will something like the mountain pine beetle sweep through and create this massive disturbance? Then you get big changes in whatever ecosystem develops after that. There is a lot of uncertainty.

“Even though we might not be harvesting those trees for 50 or 60 years, we can’t plant trees today planning on the climate for the 2050s, because they have to survive in 2013.”

Greg O’Neill, a B.C. forest service researcher, said one of the tactics being adopted to support ecosystems is “assisted migration.”

“Whenever we reforest, instead of using local seed, we use seed from a few hundred meters further south or seed from a couple of degrees [latitude to the south].

“Now I say that because it’s easy to explain that way. But in practice the province has very strict seed transfer guidelines when foresters go to reforest a site. We’ve made a couple of small changes to the seed transfer guidelines and we are in the process of making more comprehensive change. We have a working group on this.

“It will be a few years yet, but we are rebuilding the current reforestation seed source selection system for the province.”

We encourage all readers to share their views on our articles and blog posts. We are committed to maintaining a lively but civil forum for discussion, so we ask you to avoid personal attacks, and please keep your comments relevant and respectful. If you encounter a comment that is abusive, click the "X" in the upper right corner of the comment box to report spam or abuse. We are using Facebook commenting. Visit our FAQ page for more information.